Methods, systems, and computer program products for allocating bandwidth in a radio packet data system based on data rate estimates determined for one or more idle transmitter/sector scenarios

ABSTRACT

Bandwidth is allocated in a radio packet data system by sending achievable data rate estimate information from an access terminal to an access network. The achievable data rate estimate information is associated with scenarios corresponding to state combinations of a plurality of transmitters in the access network in which each transmitter is in either a serving, active, or idle state and one or more of the plurality of transmitters is in the idle state in one or more of the scenarios.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to wireless communicationtechnology, and, more particularly, to methods, systems, and computerprogram products for allocating bandwidth in a radio packet data system.

[0002] A radio packet data system generally comprises an access network(AN), a plurality of access terminals (AT), and the air interfacedefined between the two. The AN may further comprise a plurality of basestations or sectors with each of the base stations/sectors having aradio footprint associated therewith that covers a certain geographicalarea, which may overlap with those of neighboring base stations/sectors.One design metric that may be used in a best-effort radio packet datasystem is the manner in which system resources are allocated to ATsbased on the signal conditions that the ATs experience.

[0003] In general, a conventional best-effort radio packet data systemmay be designed to allocate system resources, such as frequencies and/ortime slots, to ATs in a proportional and fair manner based on thequality of the radio channel conditions that the ATs are experiencing.The ATs may communicate information to the AN that describes the qualityof the radio channel conditions. The feed back information may includesignal strength information, an ATs preferred serving basestation/sector and/or data rate.

[0004] For example, as described in the “cdma2000 High Rate Packet DataAir Inteface Specification,” Version 3.0, by the 3rd GenerationPartnership Project 2, dated Dec. 5, 2001, the disclosure of which ishereby incorporated herein by reference, an AT may request data servicefrom the AN by sending a message on the reverse link that indicateswhich base station/sector the AT prefers to receive data from and atwhat rate the data should be sent. The information fed back from an ATto the AN may be referred to as data rate control (DRC) information. Inan HDR system, an AT determines the DRC information based onmeasurements taken during receipt of pilot symbols. FIG. 1A shows thetime slot format of the HDR forward link channel. Each time slot is 1.66ms long and has 2048 chips. The time slot is divided into two sub-slots.Each sub-slot or half time slot is further divided into a pilot chipsfield, which may be used for channel estimation and/or determination ofDRC information, two medium access control (MAC) chips fields forcontrol and signaling, and two data chips fields for data payload. Thepilot field may be an all-one sequence and the MAC fields may containcontrol signaling, such as reverse power control commands and reverseactivity indication. As shown in FIG. 1B, if a base station/sector doesnot have any data to send to the ATs in its coverage area, then the basestation/sector transmits idle information during the data intervals.

[0005] In an HDR system, there are twelve data packet formats with ninedifferent data rates ranging from 38.4 kbps to 2457.6 kbps. During adata service session, an AT monitors the pilot symbols on the forwardlink and maintains a list of potential serving base stations/sectors. Onthe reverse link, the AT sends a DRC message every slot that indicatesfrom which base station/sector and at which one of the twelve data ratesit intends to receive data.

[0006] The AN receives the requests from multiple ATs in the system andschedules the data delivery to the terminals through the requested basestations/sectors and at the requested data rates using time divisionmultiplexing techniques in a manner intended to balance overallthroughput and to provide fairness. Once the AN decides to serve orallocate bandwidth to an AT, it delivers the packets from the basestation/sector requested by the AT and at the rate requested by the ATstarting two slots after the transmission of the corresponding DRCinformation. For packets comprising multiple slots, the time slots arenot transmitted consecutively. Instead, the time slots are separated bya 3-slot interval to allow time for acknowledgements from the AT toreach the AN.

[0007] As discussed above, the ATs determine the DRC information basedon measurements taken during receipt of pilot symbols. Because the basestations/sectors are synchronized in time, the signal received by an ATduring the pilot symbol interval is the superposition of the pilotsymbols from potential serving base stations/sectors. Based on thesemeasurements, an AT may determine the signal-to-interference ratio (SIR)over the pilot symbol interval for potential serving basestations/sectors and the one with the highest SIR is selected as theserving base station/sector. The highest sustainable data rate at thisSIR may then be selected as the requested rate to be included as part ofthe DRC information to be fed back to the AN. Unfortunately, this mayresult in a more pessimistic data rate estimate than may otherwise beachieved inasmuch as all base stations/sectors transmit during the pilotinterval and this may not always be the case during the data intervals.

SUMMARY OF THE INVENTION

[0008] According to some embodiments of the present invention, bandwidthis allocated in a radio packet data system by sending achievable datarate estimate information from an access terminal to an access network.The achievable data rate estimate information is associated withscenarios corresponding to state combinations of a plurality oftransmitters in the access network in which each transmitter is ineither a serving, active, or idle state and one or more of the pluralityof transmitters is in the idle state in one or more of the scenarios.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Other features of the present invention will be more readilyunderstood from the following detailed description of specificembodiments thereof when read in conjunction with the accompanyingdrawings, in which:

[0010]FIGS. 1A and 1B illustrate active and idle time slots structures,respectively, for a high data rate (HDR) radio packet data system;

[0011]FIG. 2 is a network schematic that illustrates a radio packet datasystem in accordance with embodiments of the present invention;

[0012]FIG. 3 is a block diagram that illustrates an access terminal inaccordance with embodiments of the present invention;

[0013]FIG. 4 is a block diagram that illustrates a software architecturefor use in base stations in accordance with embodiments of the presentinvention; and

[0014]FIGS. 5 and 6 are flowcharts that illustrate operations forallocating bandwidth in a radio packet data system in accordance withembodiments of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0015] While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and will herein be described in detail. Itshould be understood, however, that there is no intent to limit theinvention to the particular forms disclosed, but on the contrary, theinvention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention as defined by theclaims. Like reference numbers signify like elements throughout thedescription of the figures.

[0016] The present invention may be embodied as systems, methods, and/orcomputer program products. Accordingly, the present invention may beembodied in hardware and/or in software (including firmware, residentsoftware, micro-code, etc.). Furthermore, the present invention may takethe form of a computer program product on a computer-usable orcomputer-readable storage medium having computer-usable orcomputer-readable program code embodied in the medium for use by or inconnection with an instruction execution system. In the context of thisdocument, a computer-usable or computer-readable medium may be anymedium that can contain, store, communicate, propagate, or transport theprogram for use by or in connection with the instruction executionsystem, apparatus, or device.

[0017] The computer-usable or computer-readable medium may be, forexample but not limited to, an electronic, magnetic, optical,electromagnetic, infrared, or semiconductor system, apparatus, device,or propagation medium. More specific examples (a nonexhaustive list) ofthe computer-readable medium would include the following: an electricalconnection having one or more wires, a portable computer diskette, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,and a portable compact disc read-only memory (CD-ROM). Note that thecomputer-usable or computer-readable medium could even be paper oranother suitable medium upon which the program is printed, as theprogram can be electronically captured, via, for instance, opticalscanning of the paper or other medium, then compiled, interpreted, orotherwise processed in a suitable manner, if necessary, and then storedin a computer memory.

[0018] Referring now to FIG. 2, an exemplary radio packet data system200, in accordance with embodiments of the present invention, comprisesone or more access terminals (ATs) 202 a,b, a plurality of mobile database stations (MDBSs) 204 a,b,c,d,e, and one or more base stationcontrollers 206. As used herein, the term “access terminal” may includea cellular radiotelephone with or without a multi-line display; aPersonal Communications System (PCS) terminal that may combine acellular radiotelephone with data processing, facsimile and datacommunications capabilities; a personal digital assistant (PDA) that caninclude a radiotelephone, pager, Intemet/intranet access, Web browser,organizer, calendar and/or a GPS receiver; and a conventional laptopand/or palmtop receiver or other appliance that includes aradiotelephone transceiver. Access terminals may also be referred to as“pervasive computing” devices. The MDBSs may be associated with service“fsectors.”The access terminals 202 a,b communicate via the plurality ofmobile data base stations (MDBSs) 204 a,b,c,d,e. As used herein, theterm “communicate” means transmit, receive, and/or both transmit andreceive. A function of the MDBSs 204 a,b,c,d,e is to handle radiocommunication with the access terminals 202 a,b. In this capacity, theMDBSs 204 a,b,c,d,e may function as a relay station for data and/orvoice signals. Thus, each MDBS may comprise a receiver and atransmitter. For purposes of illustration, only five MDBSs 204 a,b,c,d,eare shown in FIG. 2. It will be understood, however, that the radiopacket data system 200 may comprise hundreds of MDBSs, and may servethousands of access terminals. According to embodiments of the presentiinvention, one or more of the access terminals 202 a,b comprises a datarate estimator module, which may be configured to determinesignal-to-interference (SIR) (Ec/Nt) ratios for communcation channelsand/or to estimate achievable data rates for communication with variousMDBSs/sectors.

[0019] The MDBSs 204 a,b,c,d,e may also communicate with the basestation controller 206. The base station controller 206 may comprisestored program control and processor resources for managing the radiopacket data system 200. According to embodiments of the presentinvention, these resources include a bandwidth allocator/servicescheduler module, which may be configured to process SIRs and/orachievable data rate estimates received from access terminals in a radiopacket data system and to schedule data delivery to the accessterminals. It will be understood that, in accordance with otherembodiments of the present invention, the functionality associated withthe bandwidth allocator/service scheduler module may be implemented inanother data processing system, in one of the MDBSs 204 a,b,c,d,e, ordistributed throughout the MDBSs 204 a,b,c,d,e or another distributedprocessing system. The communication connection between the MDBSs 204a,b,c,d,e and the base station controller 206 may be, for example, butnot limited to, a wireless connection, a wireline connection, and/or aninput/output bus interface that may facilitate the exchange ofinformation between devices for MDBSs 204 a,b,c,d,e that are co-locatedwith the base station controller 206.

[0020] Although FIG. 2 illustrates an exemplary radio packet datanetwork 200 architecture, it will be understood that the presentinvention is not limited to such a configuration, but is intended toencompass any configuration capable of carrying out the operationsdescribed herein.

[0021]FIG. 3 illustrates an access terminal 300 that may be used inembodiments of the access terminals 202 a,b of FIG. 2, in accordancewith the present invention. The access terminal 300 comprises akeyboard/keypad 302, a display 304, a transceiver 306, a memory 308, amicrophone 310, and a speaker 312 that communicate with a processor 314.The transceiver 306 typically comprises a transmitter circuit 316 and areceiver circuit 318, which cooperate to transmit and receive radiofrequency signals to MDBSs via an antenna 320. The radio frequencysignals transmitted between the mobile terminal 300 and the MDBSs maycomprise both traffic and control signals (e.g., paging signals/messagesfor incoming calls), which are used to establish and maintaincommunication with another party or destination. The radio frequencysignals may also comprise packet data information, such as, for example,cellular digital packet data (CDPD) information. The foregoingcomponents of the access terminal 300 may be included in manyconventional access terminals and their functionality is generally knownto those skilled in the art.

[0022] The processor 314 communicates with the memory 308 via anaddress/data bus. The processor 314 may be, for example, a commerciallyavailable or custom microprocessor. The memory 308 is representative ofthe one or more memory devices containing the software and data used todetermine achievable data rate estimates, which may be communicated to aradio packet data system access network for use in allocating bandwidthin the radio packet data system, in accordance with embodiments of thepresent invention. The memory 308 may include, but is not limited to,the following types of devices: cache, ROM, PROM, EPROM, EEPROM, flash,SRAM, and DRAM.

[0023] As shown in FIG. 3, the memory 308 may contain up to two or morecategories of software and/or data: the operating system 322 and thedata rate estimation module 324. The operating system 322 generallycontrols the operation of the access terminal. In particular, theoperating system 322 may manage the access terminal's software and/orhardware resources and may coordinate execution of programs by theprocessor 314. The data rate estimation module 324 may be configured todetermineSIR ratios for channels used to communicate with variousMDBSs/sectors, which may be candidates for serving the access terminal.These SIRs may be used to estimate achievable data rates forcommunication with the various MDBSs/sectors.

[0024] As discussed above, conventional access terminals may computeSIRs and/or achievable data rate estimates for serving MDBSs/sectorsbased on measurements taken during pilot symbol transmission intervals.The MDBS/sector associated with the channel exhibiting the highest SIRand maximum achievable data rate estimate is selected as the servingMDBS/sector and the access terminal communicates this data rate and SIRto the selected MDBS/sector as a requested data rate. Thus, conventionalaccess terminals may submit a requested data rate to the access networkthat is estimated based on a single scenario in which all potentialMDBSs/sectors are active (i.e., transmitting). According to embodimentsof the present invention, the data rate estimation module 324 may beconfigured to determine channel SIRs and achievable data rate estimatesfor one or more scenarios in which one or more potential servingMDBSs/sectors are idle based on measurements taken during pilot symboltransmission intervals using conventional estimation techniques.

[0025] Although FIG. 3 illustrates an exemplary software architecturethat may be used to determine achievable data rate estimate information,which may be communicated to a radio packet data system access networkfor use in allocating bandwidth in the radio packet data system, it willbe understood that the present invention is not limited to such aconfiguration but is intended to encompass any configuration capable ofcarrying out the operations described herein.

[0026]FIG. 4 illustrates a processor 400 and a memory 402 that may beused in embodiments of the base station controller 206 of FIG. 2 inaccordance with the present invention. The processor 400 communicateswith the memory 402 via an address/data bus 404. The processor 400 maybe, for example, a commercially available or custom microprocessor. Thememory 402 is representative of the one or more memory devicescontaining the software and data used to allocate bandwidth in a radiopacket data system in accordance with embodiments of the presentinvention. The memory 402 may include, but is not limited to, thefollowing types of devices: cache, ROM, PROM, EPROM, EEPROM, flash,SRAM, and DRAM.

[0027] As shown in FIG. 4, the memory 404 may contain up to three ormore categories of software and/or data: an operating system 406, abandwidth allocation and service scheduling module 408, and a datamodule 410. The operating system 406 generally controls the operation ofthe base station controller. In particular, the operating system 406 maymanage the base station controller's software and/or hardware resourcesand may coordinate execution of programs by the processor 400. Thebandwidth allocation and service scheduling module 408 may be configuredto process SIRs and/or achievable data rate estimates received fromaccess terminals in a radio packet data system and to schedule datadelivery to the access terminals using various multiplexing techniques,such as TDMA, CDMA, and or FDMA, in a manner intended to balance overallthroughput and to provide fairness. The data module 410 may contain theSIR and/or achievable data rate estimates that are received from theaccess terminals in the radio packet data system.

[0028] Although FIG. 4 illustrates an exemplary base station controllersoftware architecture that may facilitate bandwidth allocation in aradio packet data system in accordance with embodiments of the presentinvention, it will be understood that the present invention is notlimited to such a configuration but is intended to encompass anyconfiguration capable of carrying out operations described herein.

[0029] Computer program code for carrying out operations of therespective access terminal and base station controller program modulesdiscussed above with respect to FIGS. 3 and 4 may be written in ahigh-level programming language, such as C or C++, for developmentconvenience. En addition, computer program code for carrying outoperations of the present invention may also be written in otherprogramming languages, such as, but not limited to, interpretedlanguages. Some modules or routines may be written in assembly languageor even micro-code to enhance performance and/or memory usage. It willbe further appreciated that the functionality of any or all of theprogram modules may also be implemented using discrete hardwarecomponents, one or more application specific integrated circuits(ASICs), or a programmed digital signal processor or microcontroller.

[0030] The present invention is described hereinafter with reference toflowchart and/or block diagram illustrations of methods, systems, andcomputer program products in accordance with exemplary embodiments ofthe invention. These flowchart and/or block diagrams further illustrateexemplary operations of the radio packet data system, acccess terminal,and software architectures of FIGS. 2-4. It will be understood that eachblock of the flowchart and/or block diagram illustrations, andcombinations of blocks in the flowchart and/or block diagramillustrations, may be implemented by computer program instructionsand/or hardware operations. These computer program instructions may beprovided to a processor of a general purpose computer, a special purposecomputer, or other programmable data processing apparatus to produce amachine, such that the instructions, which execute via the processor ofthe computer or other programmable data processing apparatus, createmeans for implementing the functions specified in the flowchart and/orblock diagram block or blocks.

[0031] These computer program instructions may also be stored in acomputer usable or computer-readable memory that may direct a computeror other programmable data processing apparatus to function in aparticular manner, such that the instructions stored in the computerusable or computer-readable memory produce an article of manufactureincluding instructions that implement the function specified in theflowchart and/or block diagram block or blocks.

[0032] The computer program instructions may also be loaded onto acomputer or other programmable data processing apparatus to cause aseries of operational steps to be performed on the computer or otherprogrammable apparatus to produce a computer implemented process suchthat the instructions that execute on the computer or other programmableapparatus provide steps for implementing the functions specified in theflowchart and/or block diagram block or blocks.

[0033] Referring now to FIG. 5, operations begin at block 500 where theaccess terminals (e.g., access terminals 202 a,b of FIG. 2) in a radiopacket data system send SIRs and/or achievable data rate estimates tothe access network where they are received by the MDBSs (e.g., MDBSs 204a,b,c,d,e of FIG. 2) and are forwarded to the base station controller(e.g., base station controller 206 of FIG. 2). As discussed above, eachaccess terminal may communicate achievable data rate estimateinformation to the access network corresponding to one or more scenariosin which one or more potential serving MDBSs/sectors are idle. This maybe illustrated by way of example. An access terminal that may receivedata from three potential MDBS/sector transmitters may submit twelveachievable data rate estimates to the access network, which correspondto the transmitter state combinations of Table 1 below: TABLE 1Transmitter 1 Transmitter 2 Transmitter 3 Serving Idle Idle Serving IdleActive Serving Active Idle Serving Active Active Idle Serving Idle IdleServing Active Active Serving Idle Active Serving Active Idle IdleServing Idle Active Serving Active Idle Serving Active Active Serving

[0034] As illustrated by Table 1, the access terminal may determineachievable data rate estimates based on each potential transmitter beinga serving transmitter in combination with the other transmitters beingin all possible combinations of idle and active (i.e., serving anotheraccess terminal) states.

[0035] The base station controller's bandwidth allocation and servicescheduling module 408 processes the received achievable data rateestimates and/or SIRs by looping over all valid MDBS transmitter statecombinations in the access network and, within this outer loop, loopingover each access terminal to associate each respective access terminalwith the MDBS transmitter having the highest achievable data rateestimate at block 502. This may be illustrated by way of example. Atable may be constructed for each valid combination of MDBS transmitterstates that contains the achievable data rate estimates submitted by thevarious access terminals for that state combination. For example, Table2 illustrates an exemplary table constructed for a radio packet datasystem that comprises eight access terminals and four MDBS transmittersof which three are active and one is idle. TABLE 2 AT1 AT2 AT3 AT4 AT5AT6 AT7 AT8 (idle) (active) (active) (idle) (idle) (idle) (idle)(active) XMIT1 SIR/ N/A    4.66/1.228 M  −5.66/307200 N/A N/A N/A N/A   8.10/1.843 M (active) rate XMIT2 SIR/ N/A N/A N/A N/A N/A N/A N/A N/A(idle) rate XMIT3 SIR/ N/A  −6.86/153600 −12.15/38400 N/A N/A N/A N/A−36.67/0 (active) rate XMIT4 SIR/ N/A −47.05/0    1.56/614400 N/A N/AN/A N/A −36.01/0 (active) rate

[0036] Applying the operations of block 502 to the Table 2 example, AT2is associated with transmitter 1, AT3 is associated with transmitter 4,and AT8 is also associated with transmitter 1. This results in twoaccess terminals (AT2 and AT8) being associated with the same MDBStransmitter (transmitter 1).

[0037] Returning to FIG. 5, the bandwidth allocation and servicescheduling module 408 loops over each MDBS transmitter to determinewhether each respective transmitter has multiple access terminalsassociated therewith at block 504. If multiple access terminals areassociated with the same MDBS transmitter, then all access terminals butone are disassociated with that MDBS transmitter and associated, ifpossible, with another MDBS transmitter at block 506 based on schedulingfactors, such as traffic loading and/or respective ratios of therequested data rate to the average received data rate for accessterninals. For example, with respect to the Table 2 example, accessterminal AT8 requests a higher data rate than access terminal AT2;

[0038] however, if access terminal AT8 has a higher average receiveddata rate than access terminal AT2, then AT8 may be associated with MDBStransmitter 1 and access terminal AT2 may be disassociated with MDBStransmitter 1 for possible association with another MDBS transmitter.

[0039] For purposes of illustration, it is assumed that access terminalsAT2 and AT8 have the same average received data rates, which results inaccess terminal AT8 being associated with MDBS transmitter 1. Thebandwidth allocation and service scheduling module 408 may attempt toassociate access terminal AT2 with another transmitter by deleting ordiscarding the associated MDBS transmitters (transmitters 1 and 4 fromthe Table 2 example) and access terminals (AT3 and AT8 from Table 2),and then repeating the operations of blocks 502, 504, and 506. This isillustrated in Table 3 below: TABLE 3 AT1 AT2 AT3 AT4 AT5 A16 AT7 AT8(idle) (active) (delete) (idle) (idle) (idle) (idle) (delete) XMIT1 SIR/N/A N/A N/A N/A N/A N/A N/A N/A (delete) rate XMIT2 SIR/ N/A N/A N/A N/AN/A N/A N/A N/A (idle) rate XMIT3 SIR/ N/A −6.86/153600 N/A N/A N/A N/AN/A N/A (active) rate XMIT4 SIR/ N/A N/A N/A N/A N/A N/A N/A N/A(delete) rate

[0040] In this example, access terminal AT2 may be associated with MDBStransmitter 3.

[0041] Returning to FIG. 5, the bandwidth allocation and servicescheduling module 408 adds the achievable data rate estimates for theaccess terminals that have been successfully associated with an MDBStransmitter for the particular MDBS transmitter state scenario to obtaina global throughput estimate for the radio packet data system at block508. Once global throughput estimates have been obtained for alI thevalid MDBS transmitter state combinations or scenarios at block 508,then the bandwidth allocation and service scheduling module 408 mayallocate bandwidth to the access terminals in the radio packet datasystem at block 510 based on the MDBS transmitter state combination orscenario that has a desirable (e.g., highest) global throughputestimate.

[0042] As discussed above with respect to block 500 of FIG. 5 an accessterminal may communicate achievable data rate estimates to the accessnetwork corresponding to one or more scenarios in which one or morepotential serving MDBSs/sectors are idle. As illustrated in Table 1above, an access terminal may communicate achievable data rate estimatesto the access network for scenarios corresponding to all possible state(e.g., serving active, or idle) combinations of the MDBS transmitters inthe access network from which the access terminal may receive service.This may be a large amount of information, however, to transmit on theuplinks between the access terminals and the access network. Thus, inother embodiments of the present invention, the data rate estimateinformation communicated from an access terminal to the access networkmay be limited to scenarios that are associated with a subset of allpossible combinations of potential serving MDBS transmitter states.

[0043] Referring now to FIG. 6, operations begin at block 600 whereaccess terminals may respectively designate one MDBS transmitter/sectoras a serving transmitter/sector and then communicate SIRs and/orachievable data rate estimates to the access network, which are based onscenarios corresponding to possible state combinations of the MDBStransmitters from which the respective access terminals may receiveservice, but in which one of the MDBS transmitters is designated as theserving transmitter while the other transmitters may assume idle andactive states. The MDBSs (e.g., MDBSs 204 a,b,c,d,e of FIG. 2) receivethe SIRs and/or achievable data rate estimates and forward these data tothe base station controller (e.g., base station controller 206 of FIG.2).

[0044] The information forwarded to the access network is a subset ofthe information contained in Table 1 above. Referring again to theexample of Table 1, an access terminal may designate MDBS transmitter 1as a serving transmitter. Thus, only the information contained in Table4 below, which corresponds to the first one-third of Table 1, need becommunicated to the access network. TABLE 4 Transmitter 1 Transmitter 2Transmitter 3 Serving Idle Idle Serving Idle Active Serving Active IdleServing Active Active

[0045] The base station controller's bandwidth allocation and servicescheduling module 408 processes the received achievable data rateestimates and/or SIRs by determining an idle/active scenario for theMDBS transmitters and the access terminals based on the receivedinformation at block 602. For each serving MDBS transmitter, adetermination is made if multiple access terminals have requestedservice from the MDBS transmitter at block 604. If multiple accessterminals have requested service from the same MDBS transmitter, thendata rate estimates for those access terminals are read and one of theterminals is selected at block 606 based on scheduling factors, such astraffic loading and/or respective ratios of the requested data rate tothe average received data rate for access terminals discussed above withrespect to block 506 of FIG. 5. The MDBS transmitter provides service tothe selected terminal or the sole terminal requesting service at thedata rate estimate for the determined idle/active scenario at block 608.Note that because each access terminal designates a single MDBStransmitter/sector for service, non-selected access terminals are notassociated with another MDBS transmitter/sector.

[0046] Thus, in environments in which the communication channel qualitybetween the MDBSs and the access terminals changes relatively slowly, itmay be preferable to send more SIR/achievable data rate estimateinformation from the access terminals to the access network, asdiscussed above with reference to FIG. 5, to provide the access networkwith greater flexibility in serving the access termninals. Conversely,in environments in which the communication quality between the MDBSs andthe access terminals changes more frequently, it may be preferable forthe access terminals to designate serving MDBS transmitters/sectors toreduce the amount of SIR/achievable data rate estimate information to besent to the access network as discussed above with reference to FIG. 6.

[0047] In other embodiments, an access terminal may use blind detectiontechniques to determine whether potential serving MDBStransmitters/sectors are in an idle or active state during datatransmission intervals. Using this additional knowledge, the number ofscenarios (e.g., potential serving MDBS transmitter state combinations)may be reduced for which the access terminals provide SIRs/achievabledata rate estimates. For a system without forward activity broadcast,blind detection techniques may provide additional information for theterminal to make a sector selection and therefore enable it to receive ahigher data rate from the network. For example, an access terminal mayavoid requesting data from an MDBS transmitter/sector that is heavilyloaded even if it has the strongest signal.

[0048] For the HDR system described above, the baseband equivalentreceived samples corresponding to the data field over an observationperiod of N samples can be modeled as, $\begin{matrix}{{{r(n)} = {{\sum\limits_{k = 1}^{K}{I_{k}{\sum\limits_{l = 1}^{L}{c_{k,l}{s_{k}( {n - \tau_{k,l}} )}}}}} + {z(n)}}},} & (1)\end{matrix}$

[0049] for n=1, . . . , N, where K is the number of sectors in thenetwork, L is the number of multipaths in the channel, c_(k,l) andτ_(k,l) are the channel coefficients and delay of the l'th path from thek'th sector, s_(k) (n) is the spread spectrum signal with unit variancesent by the k'th sector, z(n) is an Additive White Gaussian Noise (AWGN)with variance N₀, and I_(k) is the on/off indicator of the k'th sector.For simplification of notations the following symbols are defined:

r=[r(1) r(2) . . . r(N)]^(T)

z=[z(1) z(2) . . . z(N)]^(T)

l=[I ₁ I ₂ . . . I _(K)]^(T)

s_(k) =[s _(k) (1) s _(k)(2) . . . s_(k)(N)]^(T)

S=[s ₁s₂ . . . s_(K)]  (2)

[0050] Note that the only unknowns in Equation (1) are the AWGN (with aknown variance), the spread spectrum signal s_(k)(n), and the indicatorI_(k). The rest of the parameters can all be obtained over the pilotbursts. Therefore, the problem becomes one of detecting the indicator Ifrom the received samples r.

[0051] The Maximal Likelihood (ML) detector for I is to find a value ofI that maximizes the conditional probability density function of thereceived samples r given the indication vector: $\begin{matrix}\begin{matrix}{\hat{I} = {\arg \quad {\max\limits_{I}\quad {f( {rI} )}}}} \\{= {\arg \quad {\max\limits_{I}{\sum\limits_{s}{{p( {SI} )}{f( {{rS},I} )}}}}}} \\{= {\arg \quad {\max\limits_{I}{\sum\limits_{s}{{p(S)}{f( {{rS},I} )}}}}}}\end{matrix} & (3)\end{matrix}$

[0052] Some manipulation leads to the following: $\begin{matrix}{{f( {{rS},I} )} \propto {\exp \{ {{- \frac{1}{N_{0}}}{\sum\limits_{n = 1}^{N}{{{r(n)} - {\sum\limits_{k = 1}^{K}{I_{k}{\sum\limits_{l - 1}^{L}{c_{k,l}{s_{k}( {n - \tau_{k,l}} )}}}}}}}^{2}}} \}} \propto {\exp \{ {\frac{1}{N_{0}}{\sum\limits_{k = 1}^{K}{{I_{k} \cdot 2}{\Re \lbrack {\sum\limits_{l = 1}^{L}{c_{k,l}^{*}{\sum\limits_{n = 1}^{N}{{r(n)}{s_{k}^{*}( {n - \tau_{k,l}} )}}}}} \rbrack}}}} \} \times \exp \{ {{- \frac{1}{N_{0}}}{\sum\limits_{n = 1}^{N}{{\sum\limits_{k = 1}^{K}{I_{k}{\sum\limits_{l = 1}^{L}{c_{k,l}{s_{k}( {n - \tau_{k,l}} )}}}}}}^{2}}} \}}} & (4)\end{matrix}$

[0053] The last term in Equation (4), however, involves crosscorrelation between pairs of s_(k)'s and therefore may becomputationally too complicated to intergrate over all possiblerealizations of S. Two simplified approaches are described hereafter.

[0054] The expected value of the power of the received samplesconditioned on the indication vector I is given by $\begin{matrix}{{{P_{r}(I)}\overset{\Delta}{\equiv}{E\{ {{r(n)}}^{2} \middle| I \}}} = {{\sum\limits_{k = 1}^{K}{I_{k}{\sum\limits_{l = 1}^{L}{c_{k,l}}^{2}}}} + N_{0}}} & (5)\end{matrix}$

[0055] This can be estimated by the sample mean of the received samples:$\begin{matrix}{{\hat{P}}_{r} = {\frac{1}{N}{\sum\limits_{n = 1}^{N}{{r(n)}}^{2}}}} & (6)\end{matrix}$

[0056] Therefore, an approach to detecting the indication vector I is asfollows:

[0057] 1. Compute P_(r)(I), the conditional expected value of the powerof the received samples, for each hypothesis of I using Equation (5).

[0058] 2. Compute {circumflex over (P)}_(r), the sample mean of |r(n)|²,using Equation (6).

[0059] 3. The forward activity is detected by selecting the hypothesiswith the smallest error between P_(r)(I) and {circumflex over (P)}_(r),i.e.,

Î=arg min |P _(r)(I)−{circumflex over (P)}_(r)|  (7)

[0060] The first approach assumes no knowledge about the statisticalcharacteristic of the spread spectrum signal. In practice, the spreadspectrum signal is a sequence of modulated symbols from a knownconstellation, such as QPSK, 8-PSK or 16-QAM. In HDR, this modulation ismost likely QPSK. To exploit this property while at the same timeavoiding the complicated approach given in Equation (3), somepre-processing of the received samples r may be performed before thedetection takes place. For the k'th sector, calculated the following:$\begin{matrix}{{{q_{k}(n)}\overset{\Delta}{\equiv}{\frac{1}{E_{k}}{\sum\limits_{m = 1}^{L}{c_{k,m}^{*}{r( {n + \tau_{k,m}} )}}}}}{{{{for}\quad n} = 1},\ldots \quad,N,{where}}} & (8) \\{E_{k} = {\sum\limits_{m = 1}^{l}{c_{k,m}}^{2}}} & (9)\end{matrix}$

[0061] By collecting all the terms containing s_(k)(n) into one term,Equation (8) can be written as:

q _(k)(n)=I _(k)s_(k)(n)+z _(k)(n),   (10)

[0062] where the sum of the remaining terms and the AWGN are denoted byz_(k)(n). It can be shown that given the indication vector I, z_(k)(n)can be approximated by a conditionally independent Gaussian randomvariable with a variance givey by: $\begin{matrix}{{{\sigma_{z_{k}}^{2}(I)}\overset{\Delta}{\equiv}\quad {E\lbrack {{z_{k}(n)}}^{2} \middle| I \rbrack}} = {\frac{1}{E_{k}^{2}}( {{\sum\limits_{j = 1}^{K}{I_{k}{\sum\limits_{l = 1}^{L}{\sum\limits_{m - 1}^{L}{{c_{j,l}c_{k,m}^{*}}}^{2}}}}} - {I_{k}{\sum\limits_{m = 1}^{L}{c_{k,m}}^{4}}} + {N_{0}E_{k}}} )}} & (11)\end{matrix}$

[0063] Therefore, the probability density function of q_(k)(n)conditioned on I and s_(k)(n) is given by: $\begin{matrix}{{f( {{{q_{k}(n)}{s_{k}(n)}},I} )} = {\frac{1}{\pi \quad {\sigma_{z_{k}}^{2}(I)}}\exp \{ {- \frac{{{{q_{k}(n)} - {I_{k}{s_{k}(n)}}}}^{2}}{\sigma_{z_{k}}^{2}(I)}} \}}} & (12)\end{matrix}$

[0064] The detection problem is now converted into one of detecting theindication vector I from the processed received samples q_(k)(n), wherek=1, . . . , K and n=1, . . . , N. Let Q and q₁, . . . , q_(k) besimilarly defined as in Equation (2), then the conditional probabilitydensity function of the processed received samples Q given theindication vector I is given by: $\begin{matrix}\begin{matrix}{{f( {QI} )} = {\sum\limits_{s}{{p( {SI} )}{f( {{QS},I} )}}}} \\{= {\sum\limits_{s}{{p(S)}{\prod\limits_{k = 1}^{K}{f( {{q_{k}s_{k}},I} )}}}}} \\{= {\sum\limits_{s}{{p(S)}{\prod\limits_{k = 1}^{K}{\prod\limits_{n = 1}^{N}{f( {{{q_{k}(n)}{s_{k}(n)}},I} )}}}}}} \\{{= {\prod\limits_{k = 1}^{K}{\prod\limits_{n = 1}^{N}{\sum\limits_{s_{k}{(n)}}{{p( {s_{k}(n)} )}{f( {{{q_{k}(n)}{s_{k}(n)}},I} )}}}}}},}\end{matrix} & (13)\end{matrix}$

[0065] and its log-likelihood function is given by: $\begin{matrix}\begin{matrix}{{\Lambda ( Q \middle| I )}\overset{\Delta}{\equiv}{\ln\lbrack {f( Q \middle| I )} \rbrack}} \\{= {\sum\limits_{k = 1}^{K}{\sum\limits_{n = 1}^{N}{\ln \lbrack {\sum\limits_{s_{k}{(n)}}{{p( {s_{k}(n)} )}{f( {{{q_{k}(n)}{s_{k}(n)}},I} )}}} \rbrack}}}} \\{\overset{\Delta}{\equiv}{\sum\limits_{k = 1}^{K}{\sum\limits_{n = 1}^{N}{\lambda_{k,n}( {{q_{k}(n)}I} )}}}}\end{matrix} & (14)\end{matrix}$

[0066] The calculation of λ_(k,n)(q_(k)(n)|I) involves s_(k)(n) and,therefore, is relatively straight-forward. For QPSK, it can be shownthat $\begin{matrix}\begin{matrix}{{\lambda_{k,n}( {{q_{k}(n)}I} )} = {I_{k} \cdot \lbrack {{{com}\lbrack {{x_{k,n}(I)},{- {x_{k,n}(I)}}} \rbrack} +} }} \\{{{{com}\lbrack {{y_{k,n}(I)},{- {y_{k,n}(I)}}} \rbrack} -}} \\{ {\frac{1}{\sigma_{z_{k}}^{2}(I)} - {l\quad {n(4)}}} \rbrack -} \\{{\frac{{{q_{k}(n)}}^{2}}{\sigma_{z_{k}}^{2}(I)} - {l\quad {n\lbrack {\pi \quad {\sigma_{z_{k}}^{2}(I)}} \rbrack}}}}\end{matrix} & (15) \\{{where}\begin{matrix}{{\chi_{k,n}(I)} = {\lbrack \frac{\sqrt{2{q_{k}(n)}}}{\sigma_{z}^{2}(I)} \rbrack}} \\{{{y_{k,n}(I)} = {\lbrack \frac{\sqrt{2{q_{k}(n)}}}{\sigma_{z_{k}}^{2}(I)} \rbrack}},}\end{matrix}} & (16) \\{{and}{{{com}( {x,y} )}\overset{\Delta}{\equiv}{l\quad {{n( {e^{x} + e^{y}} )}.}}}} & (17)\end{matrix}$

[0067] In summary, the detection method described above comprises thefollowing steps:

[0068] 1. Compute q_(k)(n) for k=1, . . . K and n=1, . . . , N accordingto Equations (8) and (9).

[0069] 2. For each hypothesis of I, compute its correspondinglog-likelihood function Λ(Q|I) according to Equations (14), (15), (16)and (17).

[0070] 3. The forward activity is detected by selecting the hypothesiswith the largest log-likelihood value:

Î=arg max Λ(Q|I)   (18)

[0071] The flowcharts of FIGS. 5 and 6 illustrate the architecture,functionality, and operations of embodiments of the access terminal 300and the base station controller 206 software. In this regard, each blockrepresents a module, segment, or portion of code, which comprises one ormore executable instructions for implementing the specified logicalfunction(s). It should also be noted that in other implementations, thefunction(s) noted in the blocks may occur out of the order noted inFIGS. 5 and 6. For example, two blocks shown in succession may, in fact,be executed substantially concurrently or the blocks may sometimes beexecuted in the reverse order, depending on the functionality involved.

[0072] Many variations and modifications can be made to the preferredembodiments without substantially departing from the principles of thepresent invention. All such variations and modifications are intended tobe included herein within the scope of the present invention, as setforth in the following claims.

We claim:
 1. A method of operating a radio packet data system,comprising: communicating achievable data rate estimate informationbetween an access terminal and an access network, the achievable datarate estimate information comprising scenarios corresponding to statecombinations of a plurality of transmitters in the access network inwhich at least one of the plurality of transmitters is in the idle statein at least one of the scenarios.
 2. A method of operating a radiopacket data system, comprising: communicating achievable data rateestimate information between an access terminal and an access network,the achievable data rate estimate infonmation comprising scenarioscorresponding to all state combinations of a plurality of transmittersin the access network in which multiple ones of the plurality oftransmitters are not in a serving state in a same one of the scenarios.3. A method of operating a radio packet data system, comprising:communicating achievable data rate estimate information between anaccess terminal and an access network, the achievable data rate estimateinformation comprising a scenario in which a first transmitter in theaccess network is in a serving state and a second transmitter in theaccess network is in an idle state.
 4. The method of claim 3, whereincommunicating the achievable data rate estimate information between theaccess terminal and the access network comprises: determining a signalto interference ratio for communications between the access terminal andthe first transmitter.
 5. The method of claim 4, wherein determining thesignal to interference ratio for communications between the accessterminal and the first transmitter comprises: determining the signal tointerference ratio for communications between the access terminal andthe first transmitter based on measurements taken during a pilot symboltransmission interval.
 6. A method of operating a radio packet datasystem, comprising: designating a transmitter in an access network as aserving transmitter for an access terminal; and communicating achievabledata rate estimate information between the access terminal and theaccess network, the achievable data rate estimate information comprisinga scenario in which another transmitter in the access network from whichthe access terminal may obtain service is in an idle state.
 7. Themethod of claim 6, wherein communicating the achievable data rateestimate information between the access terminal and the access networkcomprises: determining a signal to interference ratio for communicationsbetween the access terminal and the serving transmitter.
 8. The methodof claim 7, wherein determining the signal to interference ratio forcommunications between the access terminal and the serving transmittercomprises: determining the signal to interference ratio forcommunications between the access terminal and the serving transmitterbased on measurements taken during a pilot symbol transmission interval.9. A method of operating a radio packet data system, comprising:receiving achievable data rate estimate information between ones of aplurality of access terminals and ones of a plurality of transmitters atan access network; for each one of the plurality of access terminals,associating one of the plurality of transmitters having a highestachievable data rate estimate associated therewith with the respectiveaccess terminal; determining whether respective ones of the plurality oftransmitters have been associated with multiple ones of the plurality ofaccess terminals; and for each one of the plurality of transmitters thatis associated with multiple ones of the plurality of access terminals,disassociating all but one of the multiple ones of the plurality ofaccess terminals with the respective transmitter based on servicescheduling factors respectively associated with the multiple ones of theplurality of access terminals.
 10. The method of claim 9, furthercomprising: discarding each one of the plurality of transmitters havingone of the plurality of access terminals associated therewith; and foreach disassociated one of the plurality of access terminals, associatinga non-discarded one of the plurality of transmitters having a highestachievable data rate estimate associated therewith with the respectivedisassociated access terminal.
 11. The method of claim 9, whereinrespective ones of the service scheduling factors comprise respectiveratios of achievable data rate estimates to average received data ratesof the multiple ones of the plurality of access terminals.
 12. Themethod of claim 9, further comprising: using blind detection of channelactivity at the ones of the plurality of access terminals to generatethe data rate estimation information.
 13. A method of operating a radiopacket data system, comprising: performing the following for each of aplurality of scenarios corresponding to state combinations of aplurality of transmitters in an access network: receiving achievabledata rate estimate information between ones of a plurality of accessterminals and ones of the plurality of transmitters at the accessnetwork; for each one of the plurality of access terminals, associatingone of the plurality of transmitters having a highest achievable datarate estimate associated therewith with the respective access terminal;determining whether respective ones of the plurality of transmittershave been associated with multiple ones of the plurality of accessterminals; for each one of the plurality of transmitters that isassociated with multiple ones of the plurality of access terminals,disassociating all but one of the multiple ones of the plurality ofaccess terminals with the respective transmitter based on servicescheduling factors respectively associated with the multiple ones of theplurality of access terminals; and adding the achievable data rateestimates corresponding to any associated ones of the plurality oftransmitters with ones of the plurality of access terminals to obtain aglobal throughput estimate for the respective one of the plurality ofscenarios.
 14. The method of claim 13, further comprising: allocatingbandwidth to the plurality of access terminals based on achievable datarate estimates associated with one of the plurality of scenarios havinga highest global throughput estimate.
 15. The method of claim 13,further comprising: discarding each one of the plurality of transmittershaving one of the plurality of access terminals associated therewith;and for each disassociated one of the plurality of access terminals,associating a non-discarded one of the plurality of transmitters havinga highest achievable data rate estimate associated therewith with therespective disassociated access terminal.
 16. The method of claim 13,wherein respective ones of the service scheduling factors compriserespective ratios of achievable data rate estimates to average receiveddata rates of the multiple ones of the plurality of access terminals.17. A method of operating a radio packet data system, comprising:performing the following for each of a plurality of access terminals:designating one of a plurality of transmitters in an access network as aserving transmitter for the respective one of the plurality of accessterminals; and sending achievable data rate estimate information fromthe respective one of the plurality of access terminals to the accessnetwork, the achievable data rate information comprising scenarioscorresponding to state combinations of at least one non-servingtransmitter in the access network; then performing the following foreach of a plurality of scenarios corresponding to state combinations ofthe plurality of transmitters in the access network: for each of aplurality of transmitters in the access network having achievable datarate estimates from multiple ones of the plurality of access terminalsassociated therewith, providing service to one of the plurality ofaccess terminals associated therewith based on service schedulingfactors.
 18. The method of claim 17, wherein respective ones of theservice scheduling factors comprise respective ratios of the achievabledata rate estimates to average received data rates of the multiple onesof the plurality of access terminals.
 19. A system for operating a radiopacket data system, comprising: means for communicating achievable datarate estimate information between an access terminal and an accessnetwork, the achievable data rate estimate information comprisingscenarios corresponding to state combinations of a plurality oftransmitters in the access network in which at least one of theplurality of transmitters is in the idle state in at least one of thescenarios; and means for receiving the achievable data rate estimateinformation at the access network.
 20. A system for operating a radiopacket data system, comprising: means for communicating achievable datarate estimate information between an access terminal and an accessnetwork, the achievable data rate estimate information comprisingscenarios corresponding to all state combinations of a plurality oftransmitters in the access network in which multiple ones of theplurality of transmitters are not in a serving state in a same one ofthe scenarios; and means for receiving the achievable data rate estimateinformation at the access network.
 21. A system for operating a radiopacket data system, comprising: means for communicating achievable datarate estimate information between an access terminal and an accessnetwork, the achievable data rate estimate information comprising ascenario in which a first transmitter in the access network is in aserving state and a second transmitter in the access network is in anidle state; and means for receiving the achievable data rate estimateinformation at the access network.
 22. The system of claim 21, whereinthe means for communicating the achievable data rate estimateinformation between the access terminal and the access networkcomprises: means for determining a signal to interference ratio forcommunications between the access terminal and the first transmitter.23. The system of claim 22, wherein the means for determining the signalto interference ratio for communications between the access terminal andthe first transmitter comprises: means for determining the signal tointerference ratio for communications between the access terminal andthe first transmitter based on measurements taken during a pilot symboltransmission interval.
 24. A system for operating a radio packet datasystem, comprising: means for designating a transmitter in an accessnetwork as a serving transmitter for an access terminal; and means forcommunicating achievable data rate estimate information between theaccess terminal and the access network, the achievable data rateestimate information comprising a scenario in which another transmitterin the access network from which the access terminal may obtain serviceis in an idle state.
 25. The system of claim 24, wherein the means forcommunicating the achievable data rate estimate information between theaccess terminal and the access network comprises: means for determininga signal to interference ratio for communications between the accessterminal and the serving transmitter.
 26. The system of claim 25,wherein the means for determining the signal to interference ratio forcommunications between the access terminal and the serving transmittercomprises: means for determining the signal to interference ratio forcommunications between the access terminal and the serving transmitterbased on measurements taken during a pilot symbol transmission interval.27. A system for operating a radio packet data system, comprising: meansfor receiving achievable data rate estimate information between ones ofa plurality of access terminals and ones of a plurality of transmittersat an access network; for each one of the plurality of access terminals,means for associating one of the plurality of transmitters having ahighest achievable data rate estimate associated therewith with therespective access terminal; means for determining whether respectiveones of the plurality of transmitters have been associated with multipleones of the plurality of access terminals; and for each one of theplurality of transmitters that is associated with multiple ones of theplurality of access terminals, means for disassociating all but one ofthe multiple ones of the plurality of access terminals with therespective transmitter based on service scheduling factors respectivelyassociated with the multiple ones of the plurality of access terminals.28. The system of claim 27, further comprising: means for discardingeach one of the plurality of transmitters having one of the plurality ofaccess terminals associated therewith; and for each disassociated one ofthe plurality of access terminals, means for associating a non-discardedone of the plurality of transmitters having a highest achievable datarate estimate associated therewith with the respective disassociatedaccess terminal.
 29. The system of claim 27, wherein respective ones ofthe service scheduling factors comprise respective ratios of achievabledata rate estimates to average received data rates of the multiple onesof the plurality of access terminals.
 30. The system of claim 27,further comprising: means for using blind detection of channel activityat the ones of the plurality of access tenninals to generate the datarate estimation information.
 31. A system for operating a radio packetdata system, comprising: means for perfonming for each of a plurality ofscenarios corresponding to state combinations of a plurality oftransmitters in an access network, the means for performing comprising:means for receiving achievable data rate estimate information betweenones of a plurality of access terminals and ones of the plurality oftransmitters at the access network; for each one of the plurality ofaccess terminals, means for associating one of the plurality oftransmitters having a highest achievable data rate estimate associatedtherewith with the respective access terminal; means for determiningwhether respective ones of the plurality of transmitters have beenassociated with multiple ones of the plurality of access terminals; foreach one of the plurality of transmitters that is associated withmultiple ones of the plurality of access terminals, means fordisassociating all but one of the multiple ones of the plurality ofaccess terminals with the respective transmitter based on servicescheduling factors respectively associated with the multiple ones of theplurality of access terminals; and means for adding the achievable datarate estimates corresponding to any associated ones of the-plurality oftransmitters with ones of the plurality of access terminals to obtain aglobal throughput estimate for the respective one of the plurality ofscenarios.
 32. The system of claim 31, further comprising: means forallocating bandwidth to the plurality of access tenminals based onachievable data rate estimates associated with one of the plurality ofscenarios having a highest global throughput estimate.
 33. The system ofclaim 31, further comprising: means for discarding each one of theplurality of transmitters having one of the plurality of accessterminals associated therewith; and for each disassociated one of theplurality of access terminals, means for associating a non-discarded oneof the plurality of transmitters having a highest achievable data rateestimate associated therewith with the respective disassociated accessterminal.
 34. The system of claim 31, wherein respective ones of theservice scheduling factors comprise respective ratios of achievable datarate estimates to average received data rates of the multiple ones ofthe plurality of access terminals.
 35. A system for operating a radiopacket data system, comprising: first means for performing for each of aplurality of access terminals, the first means for performingcomprising: means for designating one of a plurality of transmitters inan access network as a serving transmitter for the respective one of theplurality of access terminals; means for sending achievable data rateestimate information from the respective one of the plurality of accessterminals to the access network, the achievable data rate estimateinformation comprising scenarios corresponding to state combinations ofat least one non-serving transmitter in the access network; and secondmeans, responsive to the means for sending, for performing for each of aplurality of scenarios corresponding to state combinations of theplurality of transmitters in the access network, the second means forperforming comprising: for each of a plurality of transmitters in theaccess network having achievable data rate estimates from multiple onesof the plurality of access terminals associated therewith, means forproviding service to one of the plurality of access terminals associatedtherewith based on service scheduling factors.
 36. The system of claim35, wherein respective ones of the service scheduling factors compriserespective ratios of the achievable data rate estimates to averagereceived data rates of the multiple ones of the plurality of accessterminals.
 37. A computer program product configured to operate a radiopacket data system, comprising: a computer readable storage mediumhaving computer readable program code embodied therein, the computerreadable program code comprising: computer readable program codeconfigured to communicate achievable data rate estimate informationbetween an access terminal and an access network, the achievable datarate estimate information comprising scenarios corresponding to statecombinations of a plurality of transmitters in the access network inwhich at least one of the plurality of transmitters is in the idle statein at least one of the scenarios.
 38. A computer program productconfigured to operate a radio packet data system, comprising: a computerreadable storage medium having computer readable program code embodiedtherein, the computer readable program code comprising: computerreadable program code configured to communicate achievable data rateestimate information between an access terminal and an access network,the achievable data rate estimate information comprising scenarioscorresponding to all state combinations of a plurality of transmittersin the access network in which multiple ones of the plurality oftransmitters are not in a serving state in a same one of the scenarios.39. A computer program product configured to operate a radio packet datasystem, comprising: a computer readable storage medium having computerreadable program code embodied therein, the computer readable programcode comprising: computer readable program code configured tocommunicate achievable data rate estimate information between an accessterminal and an access network, the achievable data rate estimateinformation comprising a scenario in which a first transmitter in theaccess network is in a serving state and a second transmitter in theaccess network is in an idle state.
 40. The computer program product ofclaim 39, wherein the computer readable program code configured tocommunicate the achievable data rate estimate information between theaccess terminal and the access network comprises: computer readableprogram code configured to determine a signal to interference ratio forcommunications between the access terminal and the first transmitter.41. The computer program product of claim 40, wherein the computerreadable program code configured to determine the signal to interferenceratio for communications between the access terminal and the firsttransmitter comprises: computer readable program code configured todetermine the signal to interference ratio for communications betweenthe access terminal and the first transmitter based on measurementstaken during a pilot symbol transmission interval.
 42. A computerprogram product configured to operate a radio packet data system,comprising: a computer readable storage medium having computer readableprogram code embodied therein, the computer readable program codecomprising: computer readable program code configured to designate atransmitter in an access network as a serving transmitter for an accessterminal; and computer readable program code configured to communicateachievable data rate estimate information between the access terminaland the access network, the achievable data rate estimate informationcomprising a scenario in which another transmitter in the access networkfrom which the access terminal may obtain service is in an idle state.43. The computer program product of claim 42, wherein the computerreadable program code configured to communicate the achievable data rateestimate information between the access terminal and the access networkcomprises: computer readable program code configured to determine asignal to interference ratio for communications between the accessterminal and the serving transmitter.
 44. The computer program productof claim 43, wherein the computer readable program code configured todetermine the signal to interference ratio for communications betweenthe access terminal and the serving transmitter comprises: computerreadable program code configured to determine the signal to interferenceratio for communications between the access terminal and the servingtransmitter based on measurements taken during a pilot symboltransmission interval.
 45. A computer program product configured tooperate a radio packet data system, comprising: a computer readablestorage medium having computer readable program code embodied therein,the computer readable program code comprising: computer readable programcode configured to receive achievable data rate estimate informationbetween ones of a plurality of access terminals and ones of a pluralityof transmitters at an access network; for each one of the plurality ofaccess tenrinals, computer readable program code configured to associateone of the plurality of transmitters having a highest achievable datarate estimate associated therewith with the respective access terminal;computer readable program code configured to determine whetherrespective ones of the plurality of transmitters have been associatedwith multiple ones of the plurality of access terminals; and for eachone of the plurality of transmitters that is associated with multipleones of the plurality of access terminals, computer readable programcode configured to disassociate all but one of the multiple ones of theplurality of access terminals with the respective transmitter based onservice scheduling factors respectively associated with the multipleones of the plurality of access terminals.
 46. The computer programproduct of claim 45, further comprising: computer readable program codeconfigured to discard each one of the plurality of transmitters havingone of the plurality of access terminals associated therewith; and foreach disassociated one of the plurality of access terminals, computerreadable program code configured to associate a non-discarded one of theplurality of transmitters having a highest achievable data rate estimateassociated therewith with the respective disassociated access tenminal.47. The computer program product of claim 45, wherein respective ones ofthe service scheduling factors comprise respective ratios of achievabledata rate estimates to average received data rates of the multiple onesof the plurality of access terminals.
 48. The computer program productof claim 45, further comprising: computer readable program code forusing blind detection of channel activity at the ones of the pluralityof access terminals to generate the data rate estimation information.49. A computer program product configured to operate a radio packet datasystem, comprising: a computer readable storage medium having computerreadable program code embodied therein, the computer readable programcode comprising: computer readable program code configured to performfor each of a plurality of scenarios corresponding to state combinationsof a plurality of transmitters in an access network, the computerreadable program code configured to perform comprising: computerreadable program code configured to receive achievable data rateestimate information between ones of a plurality of access terminals andones of the plurality of transmitters at the access network; for eachone of the plurality of access terminals, computer readable program codeconfigured to associate one of the plurality of transmitters having ahighest achievable data rate estimate associated therewith with therespective access terminal; computer readable program code configured todetermine whether respective ones of the plurality of transmitters havebeen associated with multiple ones of the plurality of access terminals;for each one of the plurality of transmitters that is associated withmultiple ones of the plurality of access terminals, computer readableprogram code configured to disassociate all but one of the multiple onesof the plurality of access terminals with the respective transmitterbased on service scheduling factors respectively associated with themultiple ones of the plurality of access terminals; and computerreadable program code configured to add the achievable data rateestimates corresponding to any associated ones of the plurality oftransmitters with ones of the plurality of access terminals to obtain aglobal throughput estimate for the respective one of the plurality ofscenarios.
 50. The computer program product of claim 49, furthercomprising: computer readable program code configured to allocatebandwidth to the plurality of access terminals based on achievable datarate estimates associated with one of the plurality of scenarios havinga highest global throughput estimate.
 51. The computer program productof claim 49, further comprising: computer readable program codeconfigured to discard each one of the plurality of transmitters havingone of the plurality of access terminals associated therewith; and foreach disassociated one of the plurality of access terminals, computerreadable program code configured to associate a non-discarded one of theplurality of transmitters having a highest achievable data rate estimateassociated therewith with the respective disassociated access terminal.52. The computer program product of claim 49, wherein respective ones ofthe service scheduling factors comprise respective ratios of achievabledata rate estimates to average received data rates of the multiple onesof the plurality of access terminals.
 53. A computer program productconfigured to operate a radio packet data system, comprising: a computerreadable storage medium having computer readable program code embodiedtherein, the computer readable program code comprising: first computerreadable program code configured to perform for each of a plurality ofaccess terminals, the first computer readable program code configured toperform comprising: computer readable program code configured todesignate one of a plurality of transmitters in an access network as aserving transmitter for the respective one of the plurality of accessterminals; computer readable program code configured to send achievabledata rate estimate information from the respective one of the pluralityof access terminals to the access network, the achievable data rateinformation comprising scenarios corresponding to state combinations ofat least one non-serving transmitter in the access network; and secondcomputer readable program code, responsive to the computer readableprogram code configured to send, configured to perform for each of aplurality of scenarios corresponding to state combinations of theplurality of transmitters in the access network, the second computerreadable program code configured ot perform comprising: for each of aplurality of transmitters in the access network having achievable datarate estimates from multiple ones of the plurality of access terminalsassociated therewith, computer readable program code configured toproviding service to one of the plurality of access terminals associatedtherewith based on service scheduling factors.
 54. The computer programproduct of claim 53, wherein respective ones of the service schedulingfactors comprise respective ratios of the achievable data rate estimatesto average received data rates of the multiple ones of the plurality ofaccess terminals.